As is well understood, shade guides presently used by the dentist in matching teeth colors commonly employ 12-13 tooth samples. In use, the dentist holds this guide near a patient's mouth, in order to determine a correct shading for the face of a tooth to be crowned, or for the teeth of a denture, for example. While shade guides have been available for many years, they all generally suffer the same disadvantage in that the tooth samples are made of a porcelain type material which does not strictly conform to the tooth enamel; under different lighting conditions, it has been found that what once may have been a shading match, no longer continues. In addition, adjacent tooth samples oftentimes have no relationship, one to another, and exhibit large differences in shadings between them. When it is further realized that different manufacturers make their own shade guides, without there being any standardizations for shading in the profession, it will be apparent that the present day use of shade guides requires the giving of instructions to the laboratory to make a tooth facing "a little grayer" than sample No. 1, "a little yellower" than sample No. 2, etc. This also follows from the fact that the tooth samples represent what, over the course of years, have come to be accepted as "average" teeth, i.e., shades most often found in a patient's mouth.
It will thus be seen that while shade guides of these natures have found wide use, there still remains a need for improved shade guides and for improved techniques in their employment. However, it will be readily appreciated that before shade guides 50, 75, 100 or more tooth samples can be effectively used, the dentist must be taught to discern shading differences between a tooth sample and the tooth to which a comparison is then being made and, correspondingly, to determine when a shading match occurs.